This invention relates to photographic equipment and more particularly, it concerns a flash illumination system for cameras.
Commonly assigned U.S. Pat. No. 4,268,146 of B. K. Johnson and U.S. Pat. No. 4,231,645 of C. W. Davis, et al., disclose camera and foldable flash unit arrangements in which the flash unit is movable as part of the camera between an operative erect position and a folded storage position. In the erect position, working exterior components of both the camera (e.g., the objective lens, view finder, range finder and photometer) and the flash unit (e.g., the source of illumination) are conditioned in the conventional forwardly facing orientation for exposure of film carried in the camera. In the folded position, the flash unit fits into a complementing formation of the camera housing in a manner such that the same working components are completely enclosed by exterior casing portions of the camera and of the flash unit. As a result, not only is the use of flash illumination facilitated by simple movement of the flash unit to the erect position, but also the need for auxiliary casings and the like to protect sensitive camera components during storage and handling is completely avoided.
The arrangements disclosed in the aforementioned copending applications are particularly suited for electronic flash units in which the source of illumination is permanently contained in the flash unit housing and presented at a window in a unit housing face which moves against the camera housing when the unit is moved to the folded position. As compared with cameras equipped with disposable flash bulbs or plural flash bulb arrays, cameras equipped with a folding or otherwise "built-in" electronic flash unit entail manufacturing costs which are reflected in a higher overall camera price. In order to make available a variably priced family of cameras related in terms of structural geometry and capable of using the same film, therefore, there is a need for low-cost cameras in which a source of flash illumination is accommodated simply by a receptacle in the camera and into which a disposable flash bulb or flash bulb unit may be inserted. Although such receptacles or flash holders traditionally have been incorporated in the camera housing, the folding flash unit geometry of the aforementioned copending applications has many advantages such as providing a protective enclosure for delicate camera components as mentioned.
In contrast to electronic flash units, however, the adaptation of a pivotal flash holder for disposable bulbs for multi-bulb arrays presents several problems peculiar to the mechanical retention, electrical connection and general handling requirements of disposable flash bulb arrays. For example, the mechanical retention of the flash bulb array by the holder must be strong enough to allow pivotal movement of the holder by one who might grasp only the flash bulb array rather than the body of the holder. Damage to either the bulb array or to the holder as a result of such improper manipulation of the assembly must be avoided. Also, the mechanical or physical retention of the flash bulb array by the holder must be of sufficient structural integrity to maintain good electrical contact between bulb array terminals and contact terminals supported within the holder. Yet, in keeping manufacturing costs of the holder to a minimum these physical requirements must be attainable without complex structural components or component organizations which pose problems to manufacturing assembly.